Hyperactivity and Spelling Disability: Testing for Shared Genetic Aetiology

Abstract
— The influence of genetic Factors in the comorbidity of spelling disability arid hyperactivity was investigated in two samples of 190 and 260 Sadie sex twin pairs. The method of bivariate group heritability was used to estimate the genetic correlation for spelling disability and hyperactivity A similar though not statistically significant value for the genetic correlation was obtained for the two samples (0.29 and 0.42). It was estimated that approximately 75% of the co-occurrence of these two conditions was due to shared generic influences.